IIT-M study predicts Chennai could emit 231.9 mn tonnes of Co2 by 2040

Researchers with the prestigious Indian Institute of Technology-Madras (IIT-M) predict that Chennai could cumulatively emit 231.9 million tonnes of carbon dioxide (Co2) by 2040 from the construction and operations of buildings alone, and suggest switching to renewable sources of energy for operational requirements as an alternative.

A team of researchers from the Centre for Technologies for Low Carbon and Lean Construction, IIT-M, and the Indo-German Centre for Sustainability (IGCS) IIT M, conducted the study. The team comprised of Prof Ashwin Mahalingam, Department of Civil Engineering, and Pokhraj Nayak, former student, IIT-M.

The researchers undertook the study in three phases by leveraging geo-spatial modelling techniques to simulate how Chennai would look in 2040, and by using Life Cycle Analysis (LCA) techniques to understand the extent of carbon emissions that Chennai would accrue due to urbanisation. They also developed several scenarios where alternative building materials and energy sources are used in Chennai’s development to evaluate technologies that could lead to the largest reduction in emissions.

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“In order to achieve our emissions targets, we need to benchmark what our ‘business as usual’ emissions are likely to be in future and work backwards. This study represents a step in trying to quantitatively address this problem,” Prof Mahalingam said.

Rapid urbanization is likely to lead to an increase in built stock across the country and in India, the building industry is estimated to account for around a quarter of total CO2 emissions.

This is mainly due to the emissions that arise out of production of raw materials (such as cement & steel), their transportation to construction sites, energy used during construction and most importantly, the energy used during operation of buildings, the IIT-M said.

The geo-spatial land models developed by The Nature Conservancy showed an increase in urban built-up areas accompanied by a decrease in water and wetlands. The research team, using Life Cycle Analysis of construction activities, has estimated the CO2 released during demolition, construction (as a result of transportation of materials and construction activities), and operation of buildings.

The calculations showed that Chennai would cumulatively emit 231 million tonnes of CO2 due to energy consumed by buildings during their construction and operations, the researchers said.

They also suggested replacing traditional cement with low-carbon cement, reuse of demolition waste for future construction, and switching to renewable resources to meet the energy requirements of operating buildings as ways to reduce emissions.

The researchers found that the single largest contributor to reducing emissions was the change in energy sources. The use of clean energy sources to supply 50 per cent of a building’s operational energy needs was also likely to result in a corresponding reduction in cumulative CO2 emissions of up to 115 million tonnes, in the period between 2019 and 2040, the study said.